Linked Life Data

9929387

Source:http://linkedlifedata.com/resource/pubmed/id/9929387

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1999-3-8
pubmed:abstractText
Scorpions have survived successfully over millions of years without detectable changes in their morphology. Instead, they have developed an efficient alomonal machinery and a stinging device supporting their needs for prey and defense. They produce a large variety of polypeptidic toxins that bind and modulate ion channel conductance in excitable tissues. The binding site, mode of action, and chemical properties of many toxins have been studied extensively, but little is known about their genomic organization and diversity. Genes representing each of the major classes of Buthidae scorpion toxins, namely, "long" toxins, affecting sodium channels (alpha, depressant, and excitatory), and "short" toxins, affecting potassium and chloride channels, were isolated from a single scorpion segment and analyzed. Each toxin type was found to be encoded by a gene family. Regardless of toxin length, 3-D structure, and site of action, all genes contain A+T-rich introns that split, at a conserved location, an amino acid codon of the signal sequence. The introns vary in length and sequence but display identical boundaries, agree with the GT/AG splice junctions, and contain T-runs downstream of a putative branch point, 5'-TAAT-3'. Despite little sequence similarity among all toxin classes, the conserved gene organization, intron features, and common cysteine-stabilized alpha-helical (CSH) core connecting an alpha-helix to a three-stranded beta-sheet suggest, that they all evolved from an ancestral common progenitor. Furthermore, the vast diversity found among genomic copies, cDNAs, and their protein products for each toxin suggests an extensive evolutionary process of the scorpion "pharmaceutical factory," whose success is due, most likely, to the inherent permissiveness of the toxin exterior to structural alterations.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0022-2844
pubmed:author
pubmed:issnType
Print
pubmed:volume
48
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
187-96
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Dynamic diversification from a putative common ancestor of scorpion toxins affecting sodium, potassium, and chloride channels.
pubmed:affiliation
Department of Plant Sciences, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat-Aviv 69978, Israel.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't